Evaluating safety and stability of CNT nanocomposites exposed to environmental conditions

There is a growing interest in the development of nanocomposites consisting of organic polymers and various nanomaterials. These materials can provide unique functionalities as compared to unmodified polymers in terms of dielectric behavior, thermal and mechanical properties, and biodegradability. Composites are used extensively in civil infrastructure applications, structures, and surface coatings. The use of the materials in infrastructure applications allows high strength to weight ratios, while providing an improved time dependent resistance to environmental factors, which commonly cause occurrences of corrosion in application. Although nanomaterials are considered potentially hazardous, they are often considered safe when encapsulated into the matrix. However, the systematic research to confirm the above mentioned paradigm is lacking, despite potential risks of nanomaterials release to human health and environment. The potential release of nanomaterials would depend on nature of nanofillers and the polymer matrix, and also depend on nature of environmental exposure, e.g. combination of UV, moisture, mechanical stress, etc. Here we present results of carbon nanotube epoxy composites which have undergone photodegradation and examined using electron microscopy, FTIR, and nanoindentation to identify potential nanomaterial release. This work has applicability to the question of nanotoxicity of using nanocomposites in applications they are exposed to photodegradation processes.